| 摘要 |
In a reactive volt-ampere-hour meter, either of a pair of electric signals representative of, respectively, an AC voltage and an AC current fed to a load has the phase thereof shifted by 90 degrees to produce a signal representation of a product of the two signals. A cumulative adder cumulates the resulting product signals. A first carry pulse and a borrow pulse are generated in the event of, respectively, an overflow and an underflow during cumulation and are fed to a first and a second up-down counter, respectively. The first up-down counter up-counts the first carry pulses and down-counts the borrow pulses and generates a second carry pulse when an overflow occurs. The second up-down counter up-counts the borrow pulses and down-counts the first carry pulses and generates a third carry pulse in the event of an overflow. An up-counter up-counts the second and third carry pulses from the first and second up-down counters, respectively. The count of the up-counter is representative of the result of cumulation of the absolute values of reactive power, i.e., the amount of reactive power.
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